Mathematics

• Group (mathematics)
  Group (mathematics)
  In mathematics, a group is an algebraic structure consisting of a set together with an operation that combines any two of its elements to form a third element. To qualify as a group, the set and the operation must satisfy a few conditions called group axioms, namely closure, associativity, identity...
  
  , a set together with a binary operation satisfying certain algebraic conditions
  • Group theory
    Group theory
    In mathematics and abstract algebra, group theory studies the algebraic structures known as groups.The concept of a group is central to abstract algebra: other well-known algebraic structures, such as rings, fields, and vector spaces can all be seen as groups endowed with additional operations and...
    
    , the study of groups
  • Group action
    Group action
    In algebra and geometry, a group action is a way of describing symmetries of objects using groups. The essential elements of the object are described by a set, and the symmetries of the object are described by the symmetry group of this set, which consists of bijective transformations of the set...
    
    , a way of describing the symmetries of objects using groups
  • Group isomorphism
    Group isomorphism
    In abstract algebra, a group isomorphism is a function between two groups that sets up a one-to-one correspondence between the elements of the groups in a way that respects the given group operations. If there exists an isomorphism between two groups, then the groups are called isomorphic...
    
    , a one-to-one correspondence (function) between two groups which respects the given group operations
  • Group object
    Group object
    In category theory, a branch of mathematics, group objects are certain generalizations of groups which are built on more complicated structures than sets...
    
    , a kind of generalization of a group which is built on more complicated structures than sets

Science

• Functional group
  Functional group
  In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
  
  , a functional entity consisting of certain atoms whose presence provides a certain property to a molecule
• Group (periodic table), a column in the periodic table of chemical elements

• Cultivar group
  Cultivar group
  In naming cultivated plants, a Group is a formal classification category, under the International Code of Nomenclature for Cultivated Plants :The term "Group" was introduced in the 2004 ICNCP, replacing the "Cultivar-group" of the 1995 ICNCP.A Group is united by some common trait; for example...
  
  , a formal classification category in the International Code of Nomenclature for Cultivated Plants (ICNCP)
• Group selection
  Group selection
  In evolutionary biology, group selection refers to the idea that alleles can become fixed or spread in a population because of the benefits they bestow on groups, regardless of the alleles' effect on the fitness of individuals within that group....
  
  , in evolutionary biology, the idea that alleles can become fixed or spread in a population because of the benefits they bestow upon groups of organisms

• Galaxy groups and clusters
  Galaxy groups and clusters
  Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation. They form the densest part of the large scale structure of the universe...
  
  , a small number of galaxies near each other
  • Local Group
    Local Group
    The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...
    
    , the group containing the Milky Way Galaxy

• Group delay and phase delay
  Group delay and phase delay
  Group delay is a measure of the time delay of the amplitude envelopes of the various sinusoidal components of a signal through a device under test, and is a function of frequency for each component...
  
  
• a set of lens
  Lens (optics)
  A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...
  
  es stacked together
• Group (stratigraphy)
  Group (stratigraphy)
  A group in stratigraphy is a lithostratigraphic unit, a part of the geologic record or rock column that consists of defined rock strata. Groups are divided into formations and are sometimes themselves grouped into "supergroups"....
  
  , in geology, a lithostratigraphical
  Lithostratigraphy
  Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology...
  
   unit; a group consists of formations, or rock strata
  Stratum
  In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
  
  .

Sociology

• Social groups, a description of various human groups
  • Peer group
    Peer group
    A peer group is a social group consisting of humans. Peer groups are an informal primary group of people who share a similar or equal status and who are usually of roughly the same age, tended to travel around and interact within the social aggregate Members of a particular peer group often have...
    
    
  • Working group
    Working group
    A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...
    
    
  • Interest group
• Group action (sociology)
  Group action (sociology)
  In sociology, a group action is a situation in which a large number of agents take action simultaneously in order to achieve a common goal; their actions are usually coordinated....
  
  
• Group behaviour
  Group behaviour
  Group behaviour in sociology refers to the situations where people interact in large or small groups. The field of group dynamics deals with small groups that may reach consensus and act in a coordinated way...
  
  
• Group dynamics
  Group dynamics
  Group dynamics refers to a system of behaviors and psychological processes that occur within a social group , or between social groups...
  
  
• Group narcissism

Computing and the internet

• Group (computing)
  Group (computing)
  In computing, the term group generally refers to a grouping of users. In principle, users may belong to none, one, or many groups The primary purpose of user groups is to simplify access control to computer systems.Suppose a computer science department has a network which is shared by students and...
  
  , a collection of users or other objects
  • Group identifier (Unix)
    Group identifier (Unix)
    In Unix-like systems, multiple users can be categorized into groups. POSIX and conventional Unix file system permissions are organized into three classes, user, group, and others. The use of groups allows additional abilities to be delegated in an organized fashion, such as access to disks,...
    
    
• Group editor
  Group editor
  A group editor is a groupware application that allows a distributed group of human users to edit a share document over a computer network. Refer to collaborative editor....
  
  , a program that allows many people to edit a shared document over a computer network
• Usenet newsgroup

Other uses

• Breed Groups (dog), the group or category to which breeds of dogs are assigned by kennel clubs
• Group (auto racing)
  Group (Auto Racing)
  An FIA Group is a category of car allowed to compete in auto racing. The FIA Appendix J to the international motor sports code defines the various Groups....
  
  , a category of car allowed to compete in auto racing
  Auto racing
  Auto racing is a motorsport involving the racing of cars for competition. It is one of the world's most watched televised sports.-The beginning of racing:...
  
  .
• Group insurance
  Group Insurance
  Group insurance is an insurance that covers a group of people, usually who are the members of societies, employees of a common employer, or professionals in a common group....
  
   covering people with common characteristics
• A musical ensemble
  Musical ensemble
  A musical ensemble is a group of people who perform instrumental or vocal music. In classical music, trios or quartets either blend the sounds of musical instrument families or group together instruments from the same instrument family, such as string ensembles or wind ensembles...
  
  :
  • Boy band
    Boy band
    A boy band is loosely defined as a popular music act consisting of only male singers. The members are expected to dance as well as sing, usually giving highly choreographed performances. More often than not, boy band members do not play musical instruments, either in recording sessions or on...
    
    
  • Girl group
    Girl group
    A girl group is a popular music act featuring several young female singers who generally harmonise together.Girl groups emerged in the late 1950s as groups of young singers teamed up with behind-the-scenes songwriters and music producers to create hit singles, often featuring glossy production...
    
    
  • Groupies

See also

• Grouping (disambiguation)
  Grouping (disambiguation)
  Grouping is a form of hierarchical knowledge representation.Grouping may also refer to:* The Grouping Act, also known as the Railways Act 1921, an enactment by the British government intended to move the railways away from internal competition...
  
  
• The Group (disambiguation)
• Functional group (disambiguation)
  Functional group (disambiguation)
  The term functional group may have several meanings:*Functional group, in organic chemistry, a group of atoms responsible for the characteristic chemical reactions of a molecule*Functional group , a collection of organisms...